For a large variety of agricultural commodities, such as cocoa, coffee, grains or cereals such as wheat, corn, or rice, protection during storage to avoid the direct and indirect effects of oxygen and excessive moisture on bulk or bagged stored commodities is important. Such effects include, but are not limited to, enabling insects and fungi to flourish. It is recognized that when commodities are harvested there is a high likelihood that along with the harvested commodity, whether cereal grains, pulses, oilseeds, nuts, spices, or the beans of beverages like coffee and cocoa, insects may be contained within the commodity. Also, stored commodities are often subject to rodent attacks. If left untreated, the insect infestations can result in a rapid growth in the number of insects and destruction of the commodity. In addition, the existence of insect infestations in many instances commonly necessitates fumigation to prevent large losses, particularly when the commodities are stored for extended periods of time or during shipment to foreign countries, to protect the recipient country from the spread of such insects, quarantine control treatments are necessary. The commodities are also subject to growth of molds and the consequent release of toxins such as aflatoxins and ochratoxins.
One approach to prevent these losses is to use pesticides, such as methyl bromide, which is harmful to the environment and specifically to the ozone layer of the upper atmosphere; therefore its use has been banned as of Jan. 2005 in developed countries. These pesticides are thereby released to the environment, or more typically, pesticides are added to the commodity immediately prior to or after shipping. The use of these pesticides is undesirable as some pesticides may have an adverse effect on the health of the consumer, the workers who handle it, or to the environment. Commodities may also be adversely affected by the effects of oxidation during storage such as increased levels of free fatty acids (FFAs), for example in cocoa beans or oil seeds such as peanuts or sunflower seeds. Increase in moisture content may occur due to exposure to high external humidity, which results in the growth of fungi and other micro-organisms in the commodity. Fungi and other micro-organisms impact on the quality, nutrition purposes, safety, purity, appearance, taste, aroma and freshness of the commodity or the germination capability of seeds and the subsequent vigor of resulting seedlings.
A well-known method for long term storage of a bulk commodity utilizes a hermetically sealed enclosure formed from a flexible, low gas-permeability plastic material employing the depletion of oxygen by respiration of live insects present in the commodity and by the commodity itself. This process takes significant time and depends in part on the level of infestation to deplete the oxygen. In addition, after the insects die, the oxygen level may gradually rise due to infiltration of air through the permeable membrane or leaks and it may thus permit various oxidation effects in the stored commodity. Further, the same hermetic storage level prevents significant infiltration of water vapor which otherwise might increase the moisture level in the stored commodity to unacceptable levels.
Systems and methods for long term storage of bulk commodities in a controlled environment have been disclosed. For example, a storage container originally termed “Cube” and now called Cocoon™ is a hermetic container, which is described in Israeli patent number 87301, U.S. Pat. No. 6,609,354 and in U.S. Pat. No. 6,941,727, all of which are incorporated herein by reference in their entireties.
Even with the success of such long term storage systems, it is difficult to know whether hermeticity has been sufficiently attained or maintained over long periods of time to prevent excessive rise in oxygen or of moisture levels in the commodity until the end of the storage period—which may be up to a year or more. Such systems do not inherently provide a way to detect whether hermeticity has been lost due to leakage unless representative parameters are regularly monitored and controlled. Therefore, it would be beneficial to have a system and method for providing an indication of conditions of hermeticity and humidity inside the container without having to open the container and without letting in outside air and further to have a system and method for providing an indication of conditions of hermeticity of a container prior to loading of a commodity therein.